Test the effectiveness of neuraminidase treated tumor cells as immunotherapy in two spontaneous and three emthylcholanthrene induced mouse tumors according to the methods of Simmons et al. Using model systems in which the neuraminidase treatment is effective, the following parameters will be evaluated: dose of treated tumor cells, numbers of successive subcutaneous injections, route of treatment, and time of administration after tumor grafting. Evaluate the effectiveness of neuraminidase treated tumor cells in immunotherapy of metastatic tumor using metastatic tumor cells. Examine the effectiveness of neuraminidase modified cells in relation to the natural immunogenicity of certain target tumors to be selected in consultation with the Project Officer.